As electron-optic device size becomes ever smaller, it becomes more difficult to implement a controlled vacuum environment within a given electron-optical system. One such electron-optical system is that of a “miniature” electron-optical system, whereby one or more components of the electron-optical system, such as electron source or electron-optical column components, are significantly compact and positioned closely together. Further, in the case of a miniature electron-optical system, limited clearance space within the system limits the usefulness of traditional vacuum technologies. For instance, miniature electron-optical systems often have limited clearance space, often on the order of microns, between the electron emitter (e.g., carbon nanotube tube emitter) and the corresponding extractor of the electron source, making it difficult to control the vacuum environment within the region near the electron emitter and the extractor. It would be advantageous to provide a system and method that provides improved control of the vacuum environment of such electron-optical systems.